The present invention relates generally to devices useful for insertion of steerable catheters and scopes. More particularly, the invention describes a handgrip to be positioned over the shaft of a scope such as a colonoscope allowing measuring and recording of insertion forces coupled with measurements of shaft linear acceleration, same handgrip adapted to measure torque and rotational acceleration about the shaft of the colonoscope, as well as a resulting motion of colonoscope.
In many cases, it has been desirable to examine internal organs, passages and the like of the human body for purposes of diagnosis, biopsy, and therapeutic interventions. One method of examining the internal organs of the patient without major surgery is to insert a remote sensing device such as an endoscope into the body through a natural body orifice such as colon or a specially-prepared surgical opening.
The primary area of application of the invention is for use with a colonoscope but other devices can also be used with the handgrip of the invention. Therefore, the word “colonoscope” is used throughout this description to broadly include various types of direct vision and fiberoptic endoscopes, fiberscopes, arthoscopes, enteroscopes, laparoscopes, and other types or steerable and deflectable catheters, guidewires, cannulaes, and tubes designed to be inserted into blood vessels, tight openings and curved passages.
The use of steerable scopes for internal examination is not limited to medicine. Remote sensing devices can be used to examine the interior of otherwise inaccessible mechanical structures without opening them; such as aircraft wings, the walls of buildings, and the enclosed areas of any structure. In these cases, an internal examination, without putting a major opening in the structure, can help to determine the reason for mechanical failure or the level of corrosion levels.
The preferred area of use for the device of the present invention is in medicine, and more particularly in colonoscopy. Colonoscopy is the preferred method to screen for colorectal cancer, a disease that afflicts 115,000 patients each year in the US. Several million screening, diagnostic and therapeutic colonoscopies are performed each year in the U.S. hospitals and ambulatory surgery centers. Colonoscopy requires a physician to inspect the colonic mucosal surface by applying force to a colonoscope and advancing this flexible tube through a series of stationary and movable colonic loops.
When using a colonoscope, a common problem is to be able to maneuver the inspection end (distal end) of the scope and position it in proximity to the area of interest. This maneuvering is performed by a trained operator who uses a combination of visual inspection of images and tactile coordination to maneuver through the twists and turns found in the colon. The operator subjectively senses the resistance to maneuvers by the “feel” of the instrument and anticipates the amount of force necessary to advance the endoscope shaft forward. The application of force to the colon and its anatomic attachments can be painful. Particularly undesirable is the frequent occurrence of excessive contact pressure on an internal tissue, which can result in pain and in rare cases in colon perforation. Sedation with analgesia is frequently required to make the procedure comfortable. Preliminary studies demonstrate that a significant variation between operators exists in the level of applied push/pull force during examination procedure and that these forces can be excessive. Operator training programs are designed to reduce the variation in technique. However, training metrics remain subjective and the characterization of effective, less forceful insertion methods is not yet available. The need therefore exists to provide a device allowing for an effective, low-cost method to define best practices and to implement these practices as part of medical record keeping, training, ongoing education and quality assurance.
There is an extensive array of surgical instruments, catheters and endoscopes that can be introduced and guided into and through both solid and hollow organ systems such as gastrointestinal tract, blood vessels and heart, urologic and gynecologic systems. These devices are designed to perform a variety of functions such as illumination, spot heating or cooling, introduction of radiographic contrast materials and other fluids, surgical therapies, dilation, etc.
Examples of such guiding or steering techniques and systems for catheters may be found in U.S. Pat. No. 4,983,165 to Loiterman entitled “Guidance System For Vascular Catheter Or The Like,” U.S. Pat. No. 4,776,844 to Ueda entitled “Medical Tube,” U.S. Pat. No. 4,934,340 to Ebling et al. entitled “Device For Guiding Medical Catheters and Scopes,” U.S. Pat. No. 4,930,521 to Metzget et al. entitled“Variable Stiffness Esophageal Catheter,” U.S. Pat. No. 3,470 to Barchilon entitled “Dirigible Catheter,” U.S. Pat. No. 3,605,725 to Bentov entitled “Controlled Motion Devices,” and the Patent Cooperation Treaty (“PCT”) Patent Application No. PCT W088/00810 of Tenerz et. al. entitled “Guide For Mechanical Guiding Of A Catheter In Connection With Cardio And Vessel Examination.” These catheters, however, fail to give the operator sufficient feedback and control of the distal end of the catheter and make it difficult to manipulate the distal end to achieve a specific isolation of particular desired sections of the body vessel or cavity.
Other steerable catheters or systems have been made to try to give the physician control of the use of the catheter during surgical procedures wherein fluids and the various tools are needed for the operation by providing a flexible tube for controlling the direction of movement of the distal end of the catheter. Examples of these other attempts may be seen in the PCT Patent Application No. W091/11213 of Lundquist et al. entitled “Catheter Steering Mechanism,” European Patent Application No. 370,158 of Martin entitled “Catheter For Prolonged Access,” and U.S. Pat. No. 4,737,142 to Heckele entitled “Instrument For Examination And Treatment Of Bodily Passages.” These devices, however, still fail to provide quantitative characterization of manipulation and control over handling the catheter needed for use with the surgical tools and fluids required for an operation.
One useful design of a handgrip for colonoscope with force and torque measurement capability is described in U.S. Pat. No. 6,981,945 by the same inventors incorporated herein in its entirety by reference. The disclosed handgrip is capable of measuring and presenting to the operator the radial and longitudinal forces applied by the operator during the manipulation with the colonoscope. The handgrip includes an internal sleeve releasably positioned over the shaft of the colonoscope so that it can be disengaged and repositioned by depressing a release button.
The colonoscope manipulations might be characterized not only by applied forces to overcome the tissue resistance but also by acceleration of the endoscope shaft resulting from the applied force. The U.S. Pat. No. 7,526,402 by Tanenhouse entitled “Miniaturized Inertial Measurement Unit and Associated Methods” presents an example of a self-contained, integrated compact measurement unit in which sensors provide measurements of acceleration, linear velocity and angular rate. Increased accuracy is achieved using a noise-reducing algorithm such as wavelet cascade denoising and an error correcting algorithm such as a Kalman filter embedded in a digital signal processor device. In a particular embodiment, two sets of three angle rate sensors are oriented triaxially in opposite directions. Each set is mounted on a different sector of a base oriented normally to the other two and comprising a set of gyroscope. Signals are sent from the angle rate sensors and accelerometer for calculating a change in attitude, position, angular rate, acceleration, and/or velocity of the unit.
Importantly, just measuring force or torque applied to the shaft of colonoscope does not provide a full picture of the procedure. For example, detecting a large force applied to the colonoscope shaft without knowing whether the shaft has moved sufficiently far as a result of such force is insufficient to conclude whether shaft manipulation is proper or not.
The need therefore exists for a colonoscope handgrip able to provide extended set of parameters characterizing colonoscope maneuvering during the examination. This set may include force and torque applied to the endoscope shaft, and resulting linear and rotational accelerations, as well as speed, orientation, and position tracking. The handgrip device of the invention is preferably designed to be easy to use, inexpensive to manufacture and result in less painful and safer colonoscopies.